[0001] The present invention relates to an arrangement for adjusting the position of a first
member with respect to a second longitudinal member and for withstanding a force substantially
parallel to the second member. In particular the present invention relates to an arrangement
for adjusting the height of the seat of a chair or to an arrangement for adjusting
the height of a shelf with respect to its support bracket.
[0002] Hitherto chairs enabling the seat to be adjusted have included a screw thread arrangement
and a hydraulic arrangement. In general these systems are costly to manufacture and
are complex.
[0003] Known shelving systems include at least two support bracket members being attached
to a wall and at least one pair of brackets for supporting the shelf appending therefrom.
The brackets are coupled to the support members by way of slots provided in the support
members and a number of hooks provided on the brackets for inserting into the slots.
These types of shelving systems do not enable the shelf to be adjusted to any particular
height since the height is determined by the position of the slots and the support
members.
[0004] Furthermore, some shelving systems do not enable the height of the shelves to be
moved easily, since the ease of removing the bracket from the support members depends
upon the co-operation between the slots and the hooks and which often are over-cooperative.
[0005] An object of the present invention is to provide an arrangement for adjusting the
position of a first member with respect to a second longitudinal member and for withstanding
a force parallel to the second member whilst obviating the aforementioned difficulties.
[0006] According to the present invention there is provided an arrangement for adjusting
the position of a first member with respect to a second longitudinal member and for
withstanding a force substantially parallel to the second member, the arrangement
comprising the first member have a contact surface for abutting the second member
and for facilitating the arrangement to withstand the force, and means for pivoting
the first member with respect to the second member, whereby pivoting the first member
disjoins the contact surface of the first member from the second member, enabling
the first member to move longitudinal position with respect to the second member.
Generally the contact surface and a surface of the second member provides sufficient
frictional force for facilitating the arrangement to withstand the force. Advantageously
the contact surface and the surface on the second member may be each crenalleted for
correspondence therebetween.
[0007] Preferably the means for pivoting comprises a pivot point disposed along a line perpendicular
to said second longitudinal member and whereby the end of the contact surface is also
disposed along said line.
[0008] The first member may be disposed substantially horizontally. The arrangement may
be for use with any one of a chair, table or shelf. Also according to the present
invention there is provided a chair comprising a seat having a contact surface for
abutting a pair of upright members, and means for pivoting the seat with respect to
the upright members for enabling the height of the seat to be adjusted.
[0009] Embodiments of the present invention will now be described, by way of example only,
with reference to any one of the accompanying drawings, of which:
FIGURE 1 is a schematic perspective diagram of a chair according to a preferred embodiment;
FIGURE 2 is a schematic diagram of an arrangement according to the preferred embodiment;
FIGURE 3 is a schematic cross section through the plane XX shown in figure 2;
FIGURE 4 is a schematic cross-sectional diagram illustrating the first member having
been raised; and
FIGURE 5 is a schematic cross sectional diagram illustrating a contact surface according
to a further embodiment of the present invention.
[0010] A preferred embodiment of the present invention is shown in figure 1. The prefered
embodiment comprises a chair 2 having a first member or seat 4 coupled to a pair of
second members or back support members 6. The seat 4 is coupled to the upright member
6 by way of means 8 providing a pivot point 10. An enlarged and exploded view of means
8 is shown in figure 2.
[0011] Means 8 includes a sleeve 12 for housing the upright member 6. The sleeve 12 is cable
of sliding up and down the support member 6. The pivot point 10 comprises a bolt or
rivet or any other suitable means extending through the seat 4. Means 8 is also provided
with a pair of flanges 14, 16 for providing protective cover.
[0012] The arrangement and operation thereof can more clearly be seen in the schematic cross
sectional diagrams illustrated in figures 3 and 4. The seat 4 is provided with a contact
surface 18 along AB. Furthermore the upright member 6 may also be provided with a
contact surface 20. The contact surfaces 18, 20 must provide sufficient friction such
that the weight of the seat 4 or any additional weight thereon enables the seat 4
to remain at a static position with respect to the upright member 6. The greater the
downward force on the seat 4, the greater the frictional force between A and B of
the contact surfaces 18,20. If the seat 4 is raised and privoted about the pivot point
10 as shown in figure 4, the contact surface 18 will be become disengaged from the
upright member 6. Accordingly the height of the seat 4 may be adjusted and in the
preferred embodiment shown in figure 1 at a scale of 1:5, the seat 4 may be moved
through a range of 40cm. It has been found that the optimum angle 0 for enabling the
seat 4 to be raised yet providing adequate frictional force is 30 degrees.
[0013] The contact surface 18 and corresponding surface 20 on the upright member 6 must
provide suitable friction. This may be achieved in many ways including a roughening
of the surfaces 18,20 or having crenellated surfaces as shown in figure 5. When the
seat 4 is substantially perpendicular to the upright member 6, the crenellations along
the surfaces 18 and 20 interlock. This further embodiment shown in figure 5 has the
additional advantage that if the seat 4 is tilted at an angle 0 less than 30 degrees,
then the crenellations along BE are still interlocked with the crenellations on surface
20 and accordingly the seat 4 cannot be moved. This provided a safety function in
that if the seat 4 is slightly knocked or moved, then the seat 4 will not fall. When
the height of the seat 4 is intended to be adjusted, then the seat 4 must be pivoted
through an angle 0 greater than 30 degrees so that the surface BC is then abutting
the upright member 6. Since the surface BC is smooth, this enables the seat 4 to be
easily moved up and down the upright member 6.
[0014] The above arrangement has many applications including chairs, tables, shelves and
foldable chairs.
[0015] The aforegoing description has been given by way of example only and it will be appreciated
by a person skilled in the art that modifications may be made without departing from
the scope of the present invention
1. An arrangement for adjusting the position of a first member with respect to a second
longitudinal member and for withstanding a force substantially parallel to the second
member, the arrangement comprising the first member having a contact surface for abutting
the second member and for facilitating the arrangement to withstand the force, and
means for pivoting the first member with respect to the second member whereby pivoting
the first member disjoins the contact surface of the first member from the second
member, enabling the first member to move longitudinal position with respect to the
second member.
2. An arrangement as claimed in claim 1, in which the contact surface and a surface
of the longitudinal member provide a sufficient fictional force for facilitating the
arrangement to withstand the force.
3. An arrangement as claimed in claim or claim 2, in which the contact surface and
the surface on the second member are each crenellated, for correspondence therebetween.
4. An arrangement as claimed in any one of claims 1 to 3, in which the means for pivoting
comprises a pivot point displayed along a line substantially perpendicular to the
upright member and whereby the end of the contact surface is also disposed along the
line.
5. An arrangement as claimed in any one of the preceding claims, in which the means
for pivoting also includes means for coupling the first member to the second member.
6. An arrangement as claimed in any one of the preceding claims in which the first
member is substantially horizontal.
7. An arrangement as claimed in any one of the preceding claims, in which the arrangement
is for use with any one of a chair, table or shelf.
8. A chair comprising a seat having a contact surface for abutting a pair of upright
members, and means for pivoting the seat with respect to the upright members for enabling
the height of the seat to be adjusted.
9. An arrangement substantially as hereinbefore described with reference to any one
of figures 1 to 5.
10. A chair substantially as hereinbefore described with reference to any one of figures
1 to 5.